The present disclosure relates to the area of coating of workpieces by means of electrostatically supported atomization, in particular by means of electrostatic rotary atomization.
To coat workpieces such as vehicle bodies it is possible to use electrostatic atomizers, in particular electrostatic rotary atomizers, with so-called external charging for which a spray jet is subjected to an electrostatic field generated by external electrodes. The droplets of paint are thus charged by attachment of ions and transported to the workpiece, being for example earthed, as described, for example, in the publications DE 10202711 A1 and EP 1 362 640 B1.
The publications US 2007/0039546 A1, U.S. Pat. No. 5,163,625 A, U.S. Pat. No. 5,044,564 A, DE 102 05 593 A1, DE 37 09 508 A1, DE 36 09 240 A1 and DE 10 2005 000 983 A1 disclose further electrostatic coating devices.
One disadvantage of the known external charging concepts is that the external electrodes required to generate the electrostatic field make it more difficult to coat small areas and confined spaces such as those found inside workpieces or in the inner areas of a vehicle door or in the entry areas of a vehicle body, or coating of tightly connected individual parts on an article carrier, in particular attachment parts with small distance such as bumpers, because of their size.
Furthermore, it is generally necessary to have an expensive and extensive, usually complex, potential isolation, in particular for use of conductive paints, for example water-based paints or low-resistance solvent-based paints, in particular those with a high solids content, due to compact construction. Furthermore, such electrostatic atomizers are typically difficult to clean since the usually used six to eight external electrode fingers, which form the external electrodes, must be individually cleaned or replaced. Furthermore, for a direct charging application with a compact construction in which not yet atomized paint is placed directly under a high-voltage potential, it is necessary to have an expensive and extensive, usually complex, potential isolation, in particular for use of conductive paints, for example water-based paints.
It is the task of the present disclosure to provide exemplary illustrations of an external charging concept for an electrostatic atomizer which allows both internal coating as well as external coating of workpieces, in particular of vehicle bodies and attachment parts, such as bumpers, while also permitting relatively simple cleaning of the electrostatic atomizer.